// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_CHILD_INDEXED_DB_WEBIDBCURSOR_IMPL_H_
#define CONTENT_CHILD_INDEXED_DB_WEBIDBCURSOR_IMPL_H_

#include <stdint.h>

#include <deque>
#include <vector>

#include "base/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "content/common/content_export.h"
#include "content/common/indexed_db/indexed_db.mojom.h"
#include "content/common/indexed_db/indexed_db_key.h"
#include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBCallbacks.h"
#include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBCursor.h"
#include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBKey.h"
#include "third_party/WebKit/public/platform/modules/indexeddb/WebIDBValue.h"

namespace base {
class SingleThreadTaskRunner;
}

namespace content {

class CONTENT_EXPORT WebIDBCursorImpl
    : NON_EXPORTED_BASE(public blink::WebIDBCursor) {
public:
    WebIDBCursorImpl(indexed_db::mojom::CursorAssociatedPtrInfo cursor,
        int64_t transaction_id,
        scoped_refptr<base::SingleThreadTaskRunner> io_runner);
    ~WebIDBCursorImpl() override;

    void advance(unsigned long count, blink::WebIDBCallbacks* callback) override;
    virtual void continueFunction(const blink::WebIDBKey& key,
        blink::WebIDBCallbacks* callback);
    void continueFunction(const blink::WebIDBKey& key,
        const blink::WebIDBKey& primary_key,
        blink::WebIDBCallbacks* callback) override;
    void postSuccessHandlerCallback() override;

    void SetPrefetchData(const std::vector<IndexedDBKey>& keys,
        const std::vector<IndexedDBKey>& primary_keys,
        const std::vector<blink::WebIDBValue>& values);

    void CachedAdvance(unsigned long count, blink::WebIDBCallbacks* callbacks);
    void CachedContinue(blink::WebIDBCallbacks* callbacks);

    // This method is virtual so it can be overridden in unit tests.
    virtual void ResetPrefetchCache();

    int64_t transaction_id() const { return transaction_id_; }

private:
    FRIEND_TEST_ALL_PREFIXES(IndexedDBDispatcherTest, CursorReset);
    FRIEND_TEST_ALL_PREFIXES(IndexedDBDispatcherTest, CursorTransactionId);
    FRIEND_TEST_ALL_PREFIXES(WebIDBCursorImplTest, AdvancePrefetchTest);
    FRIEND_TEST_ALL_PREFIXES(WebIDBCursorImplTest, PrefetchReset);
    FRIEND_TEST_ALL_PREFIXES(WebIDBCursorImplTest, PrefetchTest);

    class IOThreadHelper;

    enum { kInvalidCursorId = -1 };
    enum { kPrefetchContinueThreshold = 2 };
    enum { kMinPrefetchAmount = 5 };
    enum { kMaxPrefetchAmount = 100 };

    int64_t transaction_id_;

    IOThreadHelper* helper_;
    scoped_refptr<base::SingleThreadTaskRunner> io_runner_;

    // Prefetch cache.
    std::deque<IndexedDBKey> prefetch_keys_;
    std::deque<IndexedDBKey> prefetch_primary_keys_;
    std::deque<blink::WebIDBValue> prefetch_values_;

    // Number of continue calls that would qualify for a pre-fetch.
    int continue_count_;

    // Number of items used from the last prefetch.
    int used_prefetches_;

    // Number of onsuccess handlers we are waiting for.
    int pending_onsuccess_callbacks_;

    // Number of items to request in next prefetch.
    int prefetch_amount_;

    base::WeakPtrFactory<WebIDBCursorImpl> weak_factory_;

    DISALLOW_COPY_AND_ASSIGN(WebIDBCursorImpl);
};

} // namespace content

#endif // CONTENT_CHILD_INDEXED_DB_WEBIDBCURSOR_IMPL_H_
